Heat exchanger and refrigeration cycle apparatus equipped with the same

ABSTRACT

A compact, readily-manufacturable heat exchanger and a refrigeration cycle apparatus equipped with the same are provided. One of opposite ends of a main body in a refrigerant flowing direction is provided with a first inlet communication hole that extends in a direction of arrangement of first refrigerant channels and that communicates with all of the first refrigerant channels. The other end is provided with a first outlet communication hole that extends in the direction of arrangement of the first refrigerant channels and that communicates with all of the first refrigerant channels.

TECHNICAL FIELD

The present invention relates to a heat exchanger that exchanges heat between a first refrigerant and a second refrigerant and to a refrigeration cycle apparatus equipped with the heat exchanger.

BACKGROUND ART

Heat exchangers in the conventional art includes a first flat pipe having a flat shape and a plurality of through-holes through which a high-temperature refrigerant flows, a second flat pipe having a flat shape and a plurality of through-holes through which a low-temperature refrigerant flows, first headers connected to opposite ends of the first flat pipe, and second headers connected to opposite ends of the second flat pipe. The first flat pipe and the second flat pipe longitudinally extend in parallel to each other (i.e., in a refrigerant flowing direction), and the flat surfaces thereof are stacked in contact with each other by, for example brazing, whereby high heat exchanging performance is achieved (e.g., see Patent Literature 1).

CITATION LIST Patent Literature

-   Patent Literature 1: Japanese Unexamined Patent Application     Publication No. 2002-340485 (page 8, FIG. 1)

SUMMARY OF INVENTION Technical Problem

However, because the flat pipes are joined to each other in the heat exchanger described above, the joint surfaces act as thermal resistance, which is a problem in that the heat exchanging performance deteriorates.

Moreover, when the joining process is performed by brazing, for example, voids tend to form between the joint surfaces, which may problematically lead to deterioration in the heat exchanging performance.

Furthermore, when the joining process between the headers and the flat pipes and the joining process between the two flat pipes are to be performed simultaneously by brazing, the entire heat exchanger needs to be controlled to a uniform temperature during the process, the gaps between the headers and the flat pipes suitable for brazing need to be controlled with high precision, and so on. This is a problem in that the manufacturing process of the heat exchanger is complicated and difficult.

In addition, if multiple layers are to be stacked for increasing the heat exchanging capacity, there is a problem in terms of, for example, interference of the headers.

The present invention has been made to solve the aforementioned problems, and a first object thereof is to provide a compact, readily-manufacturable heat exchanger and a refrigeration cycle apparatus equipped with the same.

A second object of the present invention is to provide a heat exchanger and a refrigeration cycle apparatus with enhanced heat exchanging performance.

Solution to Problem

A heat exchanger according to the present invention includes a first refrigerant path in which a plurality of first refrigerant channels through which a first refrigerant flows are arranged in a single row; a second refrigerant path in which a plurality of second refrigerant channels through which a second refrigerant flows are arranged in a single row; first communication holes that are formed at opposite ends of the first refrigerant path, extend through in a direction of arrangement of the plurality of first refrigerant channels, and communicate with all of the first refrigerant channels; and second communication holes that are formed at opposite ends of the second refrigerant path, extend through in a direction of arrangement of the plurality of second refrigerant channels, and communicate with all of the second refrigerant channels. The first refrigerant flows into one of the first communication holes formed at the opposite ends of the first refrigerant path, flows through the first refrigerant channels, and flows outside via the other first communication hole. The second refrigerant flows into one of the second communication holes formed at the opposite ends of the second refrigerant path, flows through the second refrigerant channels, and flows outside via the other second communication hole. The first refrigerant channels and the second refrigerant channels extend in parallel to each other and are disposed adjacent to each other, and the first refrigerant and the second refrigerant exchange heat via a partition at adjacent surfaces of the first refrigerant channels and the second refrigerant channels.

Advantageous Effects of Invention

According to the present invention, since the first communication holes and the second communication holes are provided within the heat exchanger, additional header pipes for connecting to the first refrigerant path and the second refrigerant path do not need to be provided, whereby the heat exchanger can be made compact and the manufacturing process can be simplified.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 illustrates the structure of a heat exchanger 8 according to Embodiment 1 of the present invention.

FIG. 2 illustrates the structure of a heat exchanger 8 a according to Embodiment 2 of the present invention.

FIG. 3 illustrates the structure of a heat exchanger 8 b according to Embodiment 3 of the present invention.

FIG. 4 illustrates the structure of a heat exchanger 8 c according to Embodiment 4 of the present invention.

FIG. 5 illustrates the structure of a heat exchanger 8 d according to Embodiment 5 of the present invention.

FIG. 6 is a refrigerant circuit diagram illustrating an example of a refrigeration cycle apparatus according to Embodiment 6 of the present invention.

FIG. 7 is a refrigerant circuit diagram illustrating an example of a refrigeration cycle apparatus according to Embodiment 7 of the present invention.

FIG. 8 is a refrigerant circuit diagram illustrating an example of a refrigeration cycle apparatus according to Embodiment 8 of the present invention.

DESCRIPTION OF EMBODIMENTS Embodiment 1 Configuration of Heat Exchanger 8

FIG. 1 illustrates the structure of a heat exchanger 8 according to Embodiment 1 of the present invention. Specifically, FIG. 1( a) is a perspective view of the heat exchanger 8, FIG. 1( b) is a plan view as viewed in a direction indicated by an arrow A in FIG. 1( a), and FIG. 1( c) is a side view as viewed in a direction indicated by an arrow B in FIG. 1( a).

As shown in FIG. 1, a main body 10 of the heat exchanger 8 according to Embodiment 1 has a first refrigerant path 1 that extends through the main body 10 in the longitudinal direction thereof and that is formed by arranging a plurality of first refrigerant channels 1 a, through which a first refrigerant (e.g., high-temperature refrigerant) flows, in a single row. Moreover, a second refrigerant path 2 extending through the main body 10 in the longitudinal direction and formed by arranging a plurality of second refrigerant channels 2 a, through which a second refrigerant (e.g., low-temperature refrigerant) flows, in a single row is formed adjacent to the first refrigerant channels 1 a of the first refrigerant path 1. Therefore, the first refrigerant path 1 and the second refrigerant path 2 are integrally formed in the main body 10. The main body 10 having the first refrigerant path 1 and the second refrigerant path 2 is composed of, for example, aluminum, an aluminum alloy, copper, a copper alloy, steel, or a stainless alloy and is manufactured by, for example, extrusion or pultrusion molding.

One of the opposite ends of the main body 10 in the refrigerant flowing direction is provided with a first inlet communication hole 3 a that extends in the direction of arrangement of the first refrigerant channels 1 a and that communicates with all of the first refrigerant channels 1 a. The other end is provided with a first outlet communication hole 4 a that extends in the direction of arrangement of the first refrigerant channels 1 a and that communicates with all of the first refrigerant channels 1 a.

Furthermore, of the opposite ends of the main body 10 in the refrigerant flowing direction, the end that is provided with the first outlet communication hole 4 a is provided with a second inlet communication hole 5 a that extends in the direction of arrangement of the second refrigerant channels 2 a and that communicates with all of the second refrigerant channels 2 a. Of the opposite ends of the main body 10 in the refrigerant flowing direction, the end that is provided with the first inlet communication hole 3 a is provided with a second outlet communication hole 6 a that extends in the direction of arrangement of the second refrigerant channels 2 a and that communicates with all of the second refrigerant channels 2 a.

The first inlet communication hole 3 a and the second outlet communication hole 6 a are slightly displaced from each other in the refrigerant flowing direction of the first refrigerant channels 1 a (or the second refrigerant channels 2 a). Moreover, the first outlet communication hole 4 a and the second inlet communication hole 5 a are slightly displaced from each other in the refrigerant flowing direction of the first refrigerant channels 1 a (or the second refrigerant channels 2 a).

The extending direction of the first inlet communication hole 3 a and the first outlet communication hole 4 a does not necessary need to be orthogonal to the direction of the first refrigerant channels 1 a. Moreover, the extending direction of the second inlet communication hole 5 a and the second outlet communication hole 6 a does not necessary need to be orthogonal to the direction of the second refrigerant channels 2 a.

First ends of the first inlet communication hole 3 a, the first outlet communication hole 4 a, the second inlet communication hole 5 a, and the second outlet communication hole 6 a are open and are connected to a first inlet connection pipe 3, a first outlet connection pipe 4, a second inlet connection pipe 5, and a second outlet connection pipe 6, respectively, so as to communicate with the outside. Second ends of the first inlet communication hole 3 a, the first outlet communication hole 4 a, the second inlet communication hole 5 a, and the second outlet communication hole 6 a are closed by, for example, sealing members.

As shown in FIG. 1, the open (or closed) ends of the first inlet communication hole 3 a, the first outlet communication hole 4 a, the second inlet communication hole 5 a, and the second outlet communication hole 6 a are all disposed at the same side. However, the configuration is not limited to this; the open (or closed) ends do not need to be disposed at the same side so long as each communication hole has one end that is open and the other end that is closed.

The opposite ends of the first refrigerant channels 1 a and the second refrigerant channels 2 a extending through the main body 10 in the longitudinal direction thereof are sealed by, for example, pinching or by using sealing members (not shown).

The first inlet communication hole 3 a and the first outlet communication hole 4 a correspond to “first communication holes” according to the present invention, and the second inlet communication hole 5 a and the second outlet communication hole 6 a correspond to “second communication holes” according to the present invention.

(Heat Exchanging Operation of Heat Exchanger 8)

Next, a heat exchanging operation between the first refrigerant and the second refrigerant in the heat exchanger 8 will be described with reference to FIG. 1.

The first refrigerant flows into the first inlet communication hole 3 a via the first inlet connection pipe 3, flows through the first refrigerant path 1 and the first outlet communication hole 4 a in that order, and then flows out from the first outlet connection pipe 4. The second refrigerant flows into the second inlet communication hole 5 a via the second inlet connection pipe 5, flows through the second refrigerant path 2 and the second outlet communication hole 6 a in that order, and then flows out from the second outlet connection pipe 6. During that time, the first refrigerant flowing through the first refrigerant path 1 and the second refrigerant flowing through the second refrigerant path 2 exchange heat in a countercurrent manner via a partition between the two refrigerant paths.

Advantages of Embodiment 1

In the heat exchanger 8 having the above-described configuration, since the first refrigerant path 1 and the second refrigerant path 2 are integrally formed in the main body 10, thermal resistance occurring at joint surfaces in a case where a pipe through which the first refrigerant flows and a pipe through which the second refrigerant flows are separately provided is suppressed, thereby allowing for enhanced heat exchanging performance.

Furthermore, because the first inlet communication hole 3 a and the first outlet communication hole 4 a are provided within the main body 10 of the heat exchanger 8, no additional header pipe for connecting to the first refrigerant path 1 needs to be provided, whereby the heat exchanger 8 can be made compact and the manufacturing process can be simplified. This similarly applies to the second inlet communication hole 5 a and the second outlet communication hole 6 a with respect to the second refrigerant path 2.

Furthermore, because the first inlet communication hole 3 a and the second outlet communication hole 6 a are slightly displaced from each other in the refrigerant flowing direction and the first outlet communication hole 4 a and the second inlet communication hole 5 a are also slightly displaced from each other in the refrigerant flowing direction, the distance between the adjoining first and second refrigerant paths 1 and 2 can be reduced, as compared with a case where such displacement configuration is not used, whereby the heat exchanger 8 can be made compact.

Although the first refrigerant channels 1 a and the second refrigerant channels 2 a each have a rectangular shape in cross section, as shown in FIG. 1, the cross-sectional shape is not limited to this; for example, the cross-sectional shape may be polygonal, circular for increasing pressure resistibility, elongated, or ellipsoidal. In this case, it is needless to say that the cross-sectional shape of the first refrigerant channels 1 a and the cross-sectional shape of the second refrigerant channels 2 a do not need to be the same. Moreover, in order to enhance heat transferability, the heat transfer area of each refrigerant path may be increased by providing a groove in the inner surface thereof. In this case, the grooves may be formed simultaneously with the extrusion and pultrusion molding process of the heat exchanger 8 so that the manufacturing process can be simplified.

Furthermore, although the first refrigerant path 1 and the second refrigerant path 2 have the same number of refrigerant channels, as shown in FIG. 1, the configuration is not limited to this. Specifically, the two paths may have a different number of refrigerant channels in accordance with the operating conditions and the physical flow properties of the refrigerants in the heat exchanger 8 so that a favorable heat exchanger with high heat transferability and low pressure loss can be obtained.

Furthermore, although the first refrigerant path 1 and the second refrigerant path 2 are integrally formed in the main body 10, as shown in FIG. 1, the configuration is not limited to this. Specifically, if the first refrigerant path 1 and the second refrigerant path 2 are provided as separate pipes and are joined to each other by, for example, brazing, the first inlet communication hole 3 a and the first outlet communication hole 4 a may be provided in the pipe of the first refrigerant path 1 so that no additional header pipe for connecting to the refrigerant channels of the first refrigerant path 1 needs to be provided, whereby the heat exchanger can be made compact and the manufacturing process can be simplified. This similarly applies to a case where the second inlet communication hole 5 a and the second outlet communication hole 6 a are provided in the pipe of the second refrigerant path 2.

Furthermore, the first inlet connection pipe 3 and the first outlet connection pipe 4 may be formed by inserting pipes into the first inlet communication hole 3 a and the first outlet communication hole 4 a, respectively. Specifically, these inserted pipes have openings, such as slits, opening only in a direction from the first inlet communication hole 3 a toward the first outlet communication hole 4 a and in a direction from the first outlet communication hole 4 a toward the first inlet communication hole 3 a. Thus, when the opposite ends of the first refrigerant channels 1 a and the second refrigerant channels 2 a are to be sealed by, for example, brazing using sealing members, the refrigerant channels can be prevented from being narrowed due to excess sealing members entering the refrigerant channels, thereby suppressing variations in production. The same effect can be achieved for the second inlet connection pipe 5 and the second outlet connection pipe 6 by applying the same configuration thereto.

Although the first refrigerant flowing through the first refrigerant path 1 and the second refrigerant flowing through the second refrigerant path 2 exchange heat in a countercurrent manner, the two refrigerants may alternatively exchange heat by flowing parallel to each other. For example, by making the first refrigerant flow in from the first inlet connection pipe 3 and the second refrigerant flow in from the second outlet connection pipe 6, the first refrigerant and the second refrigerant are made to flow parallel to each other.

Embodiment 2

A heat exchanger 8 a according to Embodiment 2 will now be described by focusing mainly on differences from the configuration and the operation of the heat exchanger 8 according to Embodiment 1.

(Configuration of Heat Exchanger 8 a)

FIG. 2 illustrates the structure of the heat exchanger 8 a according to Embodiment 2 of the present invention.

As shown in FIG. 2, in the main body 10 of the heat exchanger 8 a according to Embodiment 2, the first refrigerant path 1 through which the first refrigerant flows is constituted of the plurality of first refrigerant channels 1 a arranged in a single row and a plurality of first refrigerant channels 1 b that are arranged in a single row adjacent to the first refrigerant channels 1 a. The second refrigerant path 2 through which the second refrigerant flows is constituted of the plurality of second refrigerant channels 2 a arranged in a single row and a plurality of second refrigerant channels 2 b that are arranged in a single row adjacent to the second refrigerant channels 2 a. In other words, the first refrigerant path 1 and the second refrigerant path 2 are each constituted of two sets of refrigerant channels, and the first refrigerant channels 1 b in the first refrigerant path 1 and the second refrigerant channels 2 a in the second refrigerant path 2 are disposed adjacent to each other, as shown in FIG. 2.

One of the opposite ends of the main body 10 in the refrigerant flowing direction is provided with the first inlet communication hole 3 a that extends in the direction of arrangement of the first refrigerant channels 1 a (and the first refrigerant channels 1 b) and that communicates with all of the first refrigerant channels 1 a and the first refrigerant channels 1 b. The other end is provided with the first outlet communication hole 4 a that extends in the direction of arrangement of the first refrigerant channels 1 a (and the first refrigerant channels 1 b) and that communicates with all of the second refrigerant channels 2 a and the second refrigerant channels 2 b.

Furthermore, of the opposite ends of the main body 10 in the refrigerant flowing direction, the end that is provided with the first outlet communication hole 4 a is provided with the second inlet communication hole 5 a that extends in the direction of arrangement of the second refrigerant channels 2 a (and the second refrigerant channels 2 b) and that communicates with all of the second refrigerant channels 2 a and the second refrigerant channels 2 b. Of the opposite ends of the main body 10 in the refrigerant flowing direction, the end that is provided with the first inlet communication hole 3 a is provided with the second outlet communication hole 6 a that extends in the direction of arrangement of the second refrigerant channels 2 a (and the second refrigerant channels 2 b) and that communicates with all of the second refrigerant channels 2 a and the second refrigerant channels 2 b.

The opposite ends of the first refrigerant channels 1 a, the first refrigerant channels 1 b, the second refrigerant channels 2 a, and the second refrigerant channels 2 b extending through the main body 10 in the longitudinal direction thereof are sealed by, for example, pinching or by using sealing members (not shown).

(Heat Exchanging Operation of Heat Exchanger 8 a)

Next, a heat exchanging operation between the first refrigerant and the second refrigerant in the heat exchanger 8 a will be described with reference to FIG. 2.

The first refrigerant flows into the first inlet communication hole 3 a via the first inlet connection pipe 3, flows through the first refrigerant channels 1 a and the first refrigerant channels 1 b constituting the first refrigerant path 1, flows through the first outlet communication hole 4 a, and then flows out from the first outlet connection pipe 4. The second refrigerant flows into the second inlet communication hole 5 a via the second inlet connection pipe 5, flows through the second refrigerant channels 2 a and the second refrigerant channels 2 b constituting the second refrigerant path 2, flows through the second outlet communication hole 6 a, and then flows out from the second outlet connection pipe 6. During that time, the first refrigerant flowing through the first refrigerant channels 1 a and the first refrigerant channels 1 b and the second refrigerant flowing through the second refrigerant channels 2 a and the second refrigerant channels 2 b exchange heat in a countercurrent manner via a partition between the first refrigerant channels 1 b and the second refrigerant channels 2 a.

Advantages of Embodiment 2

In the heat exchanger 8 a described above, even though the refrigerant paths are each constituted of multiple sets of refrigerant channels, the refrigerant channels are integrally formed. Therefore, in addition to the advantages of the heat exchanger 8 according to Embodiment 1, thermal resistance occurring in a case where the refrigerant channels are separately formed is suppressed, thereby allowing for enhanced heat exchanging performance.

Furthermore, since each refrigerant path is constituted of two sets of refrigerant channels and these refrigerant channels converge on a single communication hole, the number of communication holes can be reduced, thereby simplifying the manufacturing process of the heat exchanger 8 a.

Since a single communication hole is formed for converging two sets of refrigerant channels, the distance between the two sets of refrigerant channels of each refrigerant path can be reduced, whereby the heat exchanger 8 a can be made compact.

Furthermore, since each refrigerant path is constituted of two sets of refrigerant channels, the heat exchanging capacity can be increased.

Although the number of refrigerant channels is the same among the first refrigerant channels 1 a, the first refrigerant channels 1 b, the second refrigerant channels 2 a, and the second refrigerant channels 2 b as shown in FIG. 2, the configuration is not limited to this. Specifically, the number of refrigerant channels may be varied in accordance with the operating conditions and the physical flow properties of the refrigerants in the heat exchanger 8 a so that a favorable heat exchanger with high heat transferability and low pressure loss can be obtained.

Furthermore, although each refrigerant path is constituted of two sets of refrigerant channels (e.g., the first refrigerant path 1 is constituted of two sets of refrigerant channels, i.e., the first refrigerant channels 1 a and the first refrigerant channels 1 b), as shown in FIG. 2, the configuration is not limited to this. Specifically, for example, if the heat exchanging capacity is to be increased or if the pressure loss is to be reduced by increasing the channel area, each refrigerant path may be constituted of three or more sets of refrigerant channels. Moreover, the number of sets of refrigerant channels in the first refrigerant path 1 and the number of sets of refrigerant channels in the second refrigerant path 2 do not need to be the same.

Furthermore, the first inlet communication hole 3 a and the second outlet communication hole 6 a may be displaced from each other in the flowing direction of the first refrigerant path 1 (or the second refrigerant path 2), as in Embodiment 1. The same applies to the first outlet communication hole 4 a and the second inlet communication hole 5 b. Accordingly, the distance between the adjoining first and second refrigerant paths 1 and 2 (i.e., the distance between the first refrigerant channels 1 b and the second refrigerant channels 2 a in FIG. 2) can be reduced, whereby the heat exchanger 8 a can be made compact.

Embodiment 3

A heat exchanger 8 b according to Embodiment 3 will now be described by focusing mainly on differences from the configuration and the operation of the heat exchanger 8 according to Embodiment 1.

(Configuration of Heat Exchanger 8 b)

FIG. 3 illustrates the structure of the heat exchanger 8 b according to Embodiment 3 of the present invention. Specifically, FIG. 3( a) is a perspective view of the heat exchanger 8 b, FIG. 3( b) is a plan view as viewed in a direction indicated by an arrow A in FIG. 3( a), and FIG. 3( c) is a side view as viewed in a direction indicated by an arrow B in FIG. 3( a).

As shown in FIG. 3, in the main body 10 of the heat exchanger 8 b according to Embodiment 3, the first refrigerant path 1 through which the first refrigerant flows is constituted of the plurality of first refrigerant channels 1 a arranged in a single row and the plurality of first refrigerant channels 1 b arranged in a single row. The second refrigerant path 2 through which the second refrigerant flows is constituted of the plurality of second refrigerant channels 2 a arranged in a single row and the plurality of second refrigerant channels 2 b arranged in a single row. Moreover, the rows of the refrigerant channels in the first refrigerant path 1 and the rows of the refrigerant channels in the second refrigerant path 2 are alternately arranged. Specifically, as viewed in the direction of the arrow B in FIG. 3( a), the refrigerant channels are arranged in the following order from the top: the first refrigerant channels 1 a, the second refrigerant channels 2 a, the first refrigerant channels 1 b, and the second refrigerant channels 2 b.

One of the opposite ends of the main body 10 in the refrigerant flowing direction is provided with the first inlet communication hole 3 a that extends in the direction of arrangement of the first refrigerant channels 1 a and that communicates with all of the first refrigerant channels 1 a, and is also provided with a first inlet communication hole 3 b that extends in the direction of arrangement of the first refrigerant channels 1 b and that communicates with all of the first refrigerant channels 1 b. The other end is provided with the first outlet communication hole 4 a that extends in the direction of arrangement of the first refrigerant channels 1 a and that communicates with all of the first refrigerant channels 1 a, and is also provided with a first outlet communication hole 4 b that extends in the direction of arrangement of the first refrigerant channels 1 b and that communicates with all of the first refrigerant channels 1 b.

Moreover, of the opposite ends of the main body 10 in the refrigerant flowing direction, the end that is provided with the first outlet communication hole 4 a and the first outlet communication hole 4 b is provided with the second inlet communication hole 5 a that extends in the direction of arrangement of the second refrigerant channels 2 a and that communicates with all of the second refrigerant channels 2 a, and is also provided with a second inlet communication hole 5 b that extends in the direction of arrangement of the second refrigerant channels 2 b and that communicates with all of the second refrigerant channels 2 b. The other end is provided with the second outlet communication hole 6 a that extends in the direction of arrangement of the second refrigerant channels 2 a and that communicates with all of the second refrigerant channels 2 a, and is also provided with a second outlet communication hole 6 b that extends in the direction of arrangement of the second refrigerant channels 2 b and that communicates with all of the second refrigerant channels 2 b.

As shown in FIG. 3, the extending direction of the first inlet communication hole 3 a and the first outlet communication hole 4 a does not necessary need to be orthogonal to the direction of the first refrigerant channels 1 a. Moreover, the extending direction of the first inlet communication hole 3 b and the first outlet communication hole 4 b does not necessary need to be orthogonal to the direction of the first refrigerant channels 1 b. This similarly applies to the extending direction of the second inlet communication hole 5 a and the second inlet communication hole 5 b as well as the second outlet communication hole 6 a and the second outlet communication hole 6 b.

The opposite ends of the first inlet communication hole 3 a, the first inlet communication hole 3 b, the first outlet communication hole 4 a, the first outlet communication hole 4 b, the second inlet communication hole 5 a, the second inlet communication hole 5 b, the second outlet communication hole 6 a, and the second outlet communication hole 6 b are closed by, for example, sealing members.

Furthermore, the opposite ends of the first refrigerant channels 1 a, the first refrigerant channels 1 b, the second refrigerant channels 2 a, and the second refrigerant channels 2 b extending through the main body 10 in the longitudinal direction thereof are sealed by, for example, pinching or by using sealing members (not shown).

Furthermore, a first inlet convergence hole 31 that communicates with both the first inlet communication hole 3 a and the first inlet communication hole 3 b is formed so as to extend in the direction of arrangement thereof, and a first outlet convergence hole 41 that communicates with both the first outlet communication hole 4 a and the first outlet communication hole 4 b is formed so as to extend in the direction of arrangement thereof. Moreover, a second inlet convergence hole 51 that communicates with both the second inlet communication hole 5 a and the second inlet communication hole 5 b is formed so as to extend in the direction of arrangement thereof, and a second outlet convergence hole 61 that communicates with both the second outlet communication hole 6 a and the second outlet communication hole 6 b is formed so as to extend in the direction of arrangement thereof.

When viewed in the direction of the arrow A (plan view) in FIG. 3( a), the first inlet convergence hole 31, the first outlet convergence hole 41, the second inlet convergence hole 51, and the second outlet convergence hole 61 are all formed at the same side (i.e., at the right side in FIG. 3( b)). However, the configuration is not limited to this. Specifically, for example, the first inlet convergence hole 31 may be formed at any position so long as the position thereof is along the direction of arrangement of the first inlet communication hole 3 a and the first inlet communication hole 3 b. Furthermore, as shown in FIG. 3( a), the extending direction of the first inlet convergence hole 31 does not necessary need to be orthogonal to the extending direction of the first inlet communication hole 3 a and the first inlet communication hole 3 b. This similarly applies to the first outlet convergence hole 41, the second inlet convergence hole 51, and the second outlet convergence hole 61.

Furthermore, first ends of the first inlet convergence hole 31, the first outlet convergence hole 41, the second inlet convergence hole 51, and the second outlet convergence hole 61 are open and are connected to the first inlet connection pipe 3, the first outlet connection pipe 4, the second inlet connection pipe 5, and the second outlet connection pipe 6, respectively, so as to communicate with the outside. Second ends of the first inlet convergence hole 31, the first outlet convergence hole 41, the second inlet convergence hole 51, and the second outlet convergence hole 61 are closed by, for example, sealing members.

As shown in FIG. 3, the open (or closed) ends of the first inlet convergence hole 31, the first outlet convergence hole 41, the second inlet convergence hole 51, and the second outlet convergence hole 61 are all disposed at the same side. However, the configuration is not limited to this; the open (or closed) ends do not need to be disposed at the same side so long as each convergence hole has one end that is open and the other end that is closed.

The first inlet communication hole 3 a, the first inlet communication hole 3 b, the first outlet communication hole 4 a, and the first outlet communication hole 4 b correspond to “first communication holes” according to the present invention, and the second inlet communication hole 5 a, the second inlet communication hole 5 b, the second outlet communication hole 6 a, and the second outlet communication hole 6 b correspond to “second communication holes” according to the present invention. The first inlet convergence hole 31 and the first outlet convergence hole 41 correspond to “first convergence holes” according to the present invention, and the second inlet convergence hole 51 and the second outlet convergence hole 61 correspond to “second convergence holes” according to the present invention.

(Heat Exchanging Operation of Heat Exchanger 8 b)

Next, a heat exchanging operation between the first refrigerant and the second refrigerant in the heat exchanger 8 b will be described with reference to FIG. 3.

The first refrigerant flows into the first inlet convergence hole 31 via the first inlet connection pipe 3 and then flows into the first inlet communication hole 3 a and the first inlet communication hole 3 b. The first refrigerant flowing into the first inlet communication hole 3 a flows through the first refrigerant channels 1 a and then flows out to the first outlet communication hole 4 a. The first refrigerant flowing into the first inlet communication hole 3 b flows through the first refrigerant channels 1 b and then flows out to the first outlet communication hole 4 b. Then, the first refrigerant flowing out to the first outlet communication hole 4 a and the first refrigerant flowing out to the first outlet communication hole 4 b merge at the first outlet convergence hole 41 before flowing out from the first outlet connection pipe 4.

The second refrigerant flows into the second inlet convergence hole 51 via the second inlet connection pipe 5 and then flows into the second inlet communication hole 5 a and the second inlet communication hole 5 b. The second refrigerant flowing into the second inlet communication hole 5 a flows through the second refrigerant channels 2 a and then flows out to the second outlet communication hole 6 a. The second refrigerant flowing into the second inlet communication hole 5 b flows through the second refrigerant channels 2 b and then flows out to the second outlet communication hole 6 b. The second refrigerant flowing out to the second outlet communication hole 6 a and the second refrigerant flowing out to the second outlet communication hole 6 b merge at the second outlet convergence hole 61 before flowing out from the second outlet connection pipe 6.

The first refrigerant flowing through the first refrigerant channels 1 a and the first refrigerant channels 1 b and the second refrigerant flowing through the second refrigerant channels 2 a and the second refrigerant channels 2 b exchange heat in a countercurrent manner via partitions between the refrigerant channels.

Advantages of Embodiment 3

In the heat exchanger 8 b described above, even though the refrigerant paths are each constituted of two sets of refrigerant channels, the refrigerant channels are integrally formed. Therefore, in addition to the advantages of the heat exchanger 8 according to Embodiment 1, thermal resistance occurring in a case where the refrigerant channels are separately formed is suppressed, thereby allowing for enhanced heat exchanging performance.

Furthermore, because the first inlet convergence hole 31 and the first outlet convergence hole 41 are provided within the main body 10 of the heat exchanger 8 b, additional header pipes for connecting to the first inlet communication hole 3 a, the first inlet communication hole 3 b, the first outlet communication hole 4 a, and the first outlet communication hole 4 b do not need to be provided. Thus, the heat exchanger 8 can be made compact and the manufacturing process can be simplified. This similarly applies to the second inlet convergence hole 51 and the second outlet convergence hole 61.

Furthermore, since each refrigerant path is constituted of two sets of refrigerant channels and these refrigerant channels converge on a single communication hole, the number of communication holes can be reduced, thereby simplifying the manufacturing process of the heat exchanger 8 b.

Moreover, since each refrigerant path is constituted of two sets of refrigerant channels, the heat exchanging capacity can be increased.

Unlike the heat exchanger 8 a according to Embodiment 2, the first refrigerant path 1 constituted of two sets of refrigerant channels and the second refrigerant path 2 constituted of two sets of refrigerant channels are not disposed adjacent to each other in the heat exchanger 8 b according to Embodiment 3. Instead, the rows of the refrigerant channels of the first refrigerant path 1 and the rows of the refrigerant channels of the second refrigerant path 2 are alternately arranged. Thus, the refrigerant flowing through the refrigerant channels of each set and the refrigerant flowing through the refrigerant channels of another set that is adjacent thereto have different structures, so that the heat exchanging performance is further enhanced, as compared with that of the heat exchanger 8 a according to Embodiment 2.

Although the first refrigerant path 1 and the second refrigerant path 2 are integrally formed in the main body 10, as shown in FIG. 3, the configuration is not limited to this. Specifically, if the first refrigerant path 1 and the second refrigerant path 2 are provided as separate pipes and are joined to each other by, for example, brazing, the first inlet communication hole 3 a, the first inlet communication hole 3 b, the first outlet communication hole 4 a, and the first outlet communication hole 4 b may be provided in the pipe of the first refrigerant path 1 so that an additional header pipe for connecting to the refrigerant channels of the first refrigerant path 1 does not need to be provided, whereby the heat exchanger can be made compact and the manufacturing process can be simplified. This similarly applies to a case where the second inlet communication hole 5 a, the second inlet communication hole 5 b, the second outlet communication hole 6 a, and the second outlet communication hole 6 b are provided in the pipe of the second refrigerant path 2.

Furthermore, although each refrigerant path is constituted of two sets of refrigerant channels (e.g., the first refrigerant path 1 is constituted of two sets of refrigerant channels, i.e., the first refrigerant channels 1 a and the first refrigerant channels 1 b), as shown in FIG. 3, the configuration is not limited to this. Specifically, for example, if the heat exchanging capacity is to be increased or if the pressure loss is to be reduced by increasing the channel area, each refrigerant path may be constituted of three or more sets of refrigerant channels. Moreover, the number of sets of refrigerant channels in the first refrigerant path 1 and the number of sets of refrigerant channels in the second refrigerant path 2 do not need to be the same.

Embodiment 4

A heat exchanger 8 c according to Embodiment 4 will now be described by focusing mainly on differences from the configuration and the operation of the heat exchanger 8 according to Embodiment 1.

(Configuration of Heat Exchanger 8 c)

FIG. 4 illustrates the structure of the heat exchanger 8 c according to Embodiment 4 of the present invention.

As shown in FIG. 4, in the heat exchanger 8 c according to Embodiment 4, one of the opposite ends of the main body 10 in the refrigerant flowing direction is provided with a first inlet communication hole 3 aa that extends in the direction of arrangement of the first refrigerant channels 1 a and that communicates with one or more of the first refrigerant channels 1 a (referred to as “first first refrigerant channel group” hereinafter). Moreover, a first inlet communication hole 3 ab that communicates with the remaining first refrigerant channel or channels 1 a is formed.

The other end is provided with a first outlet communication hole 4 aa that extends in the direction of arrangement of the first refrigerant channels 1 a. Among the first refrigerant channels 1 a, the first outlet communication hole 4 aa communicates with all of the first refrigerant channels 1 a communicating with the first inlet communication hole 3 aa and also communicates with one or more of the first refrigerant channels 1 a (referred to as “second first refrigerant channel group” hereinafter) that communicate with the first inlet communication hole 3 ab. Moreover, a first outlet communication hole 4 ab that communicates with the remaining first refrigerant channel or channels 1 a (referred to as “third first refrigerant channel group” hereinafter) communicating with the first inlet communication hole 3 ab is also formed.

Furthermore, of the opposite ends of the main body 10 in the refrigerant flowing direction, the end that is provided with the first outlet communication hole 4 aa and the first outlet communication hole 4 ab is provided with a second inlet communication hole 5 ab that extends in the direction of arrangement of the second refrigerant channels 2 a and that communicates with one or more of the second refrigerant channels 2 a (referred to as “first second refrigerant channel group” hereinafter). Moreover, a second inlet communication hole 5 aa that communicates with the remaining second refrigerant channel or channels 2 a is also formed.

Furthermore, of the opposite ends of the main body 10 in the refrigerant flowing direction, the end that is provided with the first inlet communication hole 3 aa and the first inlet communication hole 3 ab is provided with a second outlet communication hole 6 ab that extends in the direction of arrangement of the second refrigerant channels 2 a. Among the second refrigerant channels 2 a, the second outlet communication hole 6 ab communicates with all of the second refrigerant channels 2 a communicating with the second inlet communication hole 5 ab and also communicates with one or more of the second refrigerant channels 2 a (referred to as “second second refrigerant channel group” hereinafter) communicating with the second inlet communication hole 5 aa. Moreover, a second outlet communication hole 6 aa that communicates with the remaining second refrigerant channel or channels 2 a (referred to as “third second refrigerant channel group” hereinafter) communicating with the second inlet communication hole 5 aa is also formed.

The “first first refrigerant channel group” is formed adjacent to the “third second refrigerant channel group”, the “second first refrigerant channel group” is formed adjacent to the “second second refrigerant channel group”, and the “third first refrigerant channel group” is formed adjacent to the “first second refrigerant channel group”.

In the refrigerant flowing direction of the first refrigerant channels 1 a (or the second refrigerant channels 2 a), the first inlet communication hole 3 aa and the second outlet communication hole 6 aa are slightly displaced from each other, and the first inlet communication hole 3 ab and the second outlet communication hole 6 ab are slightly displaced from each other. Moreover, in the refrigerant flowing direction of the first refrigerant channels 1 a (or the second refrigerant channels 2 a), the first outlet communication hole 4 aa and the second inlet communication hole 5 aa are slightly displaced from each other, and the first outlet communication hole 4 ab and the second inlet communication hole 5 ab are slightly displaced from each other.

The first inlet communication hole 3 aa, the first inlet communication hole 3 ab, the first outlet communication hole 4 aa, and the first outlet communication hole 4 ab do not necessarily need to extend orthogonally to the direction of the first refrigerant channels 1 a. Likewise, the second inlet communication hole 5 aa, the second inlet communication hole 5 ab, the second outlet communication hole 6 aa, and the second outlet communication hole 6 ab do not necessarily need to extend orthogonally to the direction of the second refrigerant channels 2 a.

Furthermore, although the first inlet communication hole 3 aa and the first inlet communication hole 3 ab extend in the same direction and are coaxial with each other, as shown in FIG. 4, the two holes do not necessarily have to extend in the same direction or be coaxial with each other. This similarly applies to the first outlet communication hole 4 aa and the first outlet communication hole 4 ab, the second inlet communication hole 5 aa and the second inlet communication hole 5 ab, and the second outlet communication hole 6 aa and the second outlet communication hole 6 ab.

First ends of the first inlet communication hole 3 aa, the first outlet communication hole 4 ab, the second inlet communication hole 5 ab, and the second outlet communication hole 6 aa are open and are connected to the first inlet connection pipe 3, the first outlet connection pipe 4, the second inlet connection pipe 5 (not shown in FIG. 4 due to being located behind the first outlet connection pipe 4), and the second outlet connection pipe 6, respectively, so as to communicate with the outside.

The first inlet communication hole 3 aa corresponds to a “first divided-communication-hole inflow section” according to the present invention, the first inlet communication hole 3 ab and the first outlet communication hole 4 aa correspond to a “first divided-communication-hole turnaround section” according to the present invention, and the first outlet communication hole 4 ab corresponds to a “first divided-communication-hole outflow section” according to the present invention. The second inlet communication hole 5 ab corresponds to a “second divided-communication-hole inflow section” according to the present invention, the second inlet communication hole 5 aa and the second outlet communication hole 6 ab correspond to a “second divided-communication-hole turnaround section” according to the present invention, and the second outlet communication hole 6 aa corresponds to a “second divided-communication-hole outflow section” according to the present invention.

(Heat Exchanging Operation of Heat Exchanger 8 c)

Next, a heat exchanging operation between the first refrigerant and the second refrigerant in the heat exchanger 8 c will be described with reference to FIG. 4.

The first refrigerant flows into the first inlet communication hole 3 aa via the first inlet connection pipe 3, flows through the first refrigerant channels 1 a, the first outlet communication hole 4 aa, the first refrigerant channels 1 a again, the first inlet communication hole 3 ab, the first refrigerant channels 1 a again, and the first outlet communication hole 4 ab in that order, and then flows out from the first outlet connection pipe 4. The second refrigerant flows into the second inlet communication hole 5 ab via the second inlet connection pipe 5, flows through the second refrigerant channels 2 a, the second outlet communication hole 6 ab, the second refrigerant channels 2 a again, the second inlet communication hole 5 aa, the second refrigerant channels 2 a again, and the second outlet communication hole 6 aa in that order, and then flows out from the second outlet connection pipe 6. During that time, the first refrigerant and the second refrigerant exchange heat in a countercurrent manner via a partition between the two refrigerant paths.

Advantages of Embodiment 4

In the heat exchanger 8 c described above, if the sectional area of the channels is to be reduced and the refrigerant flow paths are to be extended for maximizing the heat exchanging performance in accordance with the operating conditions and the physical properties of the refrigerants, the refrigerant flow paths can be turned around inside. Therefore, in addition to the advantages of the heat exchanger 8 according to Embodiment 1, the heat exchanging performance can be maximized while minimizing the size of the heat exchanger 8 c.

Furthermore, since the first inlet communication hole 3 aa and the like for turning around the refrigerant flow paths are formed within the main body 10 of the heat exchanger 8 c, additional pipes do not need to be provided, whereby the heat exchanger 8 c can be made compact.

Although the first refrigerant and the second refrigerant are both made to flow by being turned around in the heat exchanger 8 c according to Embodiment 4, the configuration is not limited to this. One of the refrigerants may be made to turn around, whereas the other refrigerant may be made to flow linearly as in Embodiment 1. In this case, the refrigerant to be made to turn around may be selected in accordance with the operating conditions and the physical properties of the refrigerants in the heat exchanger so that a favorable heat exchanger with high heat transferability and low pressure loss can be obtained.

Furthermore, the first inlet communication hole 3 aa, the first inlet communication hole 3 ab, the first outlet communication hole 4 aa, and the first outlet communication hole 4 ab may have the configurations described above, whereas the second inlet communication hole 5 aa, the second inlet communication hole 5 ab, the second outlet communication hole 6 aa, and the second outlet communication hole 6 ab may have the following configurations. However, the positional relationship between the first inlet communication holes 3 aa and 3 ab and the second outlet communication holes 6 aa and 6 ab as well as the positional relationship between the second outlet communication holes 4 aa and 4 ab and the second inlet communication holes 5 aa and 5 ab are the same as those shown in FIG. 4. Specifically, of the opposite ends of the main body 10 in the refrigerant flowing direction, the end provided with the first outlet communication hole 4 aa and the first outlet communication hole 4 ab is provided with the second inlet communication hole 5 aa that extends in the direction of arrangement of the second refrigerant channels 2 a and that communicates with one or more of the second refrigerant channels 2 a (corresponding to the “third second refrigerant channel group” described above). Moreover, the second inlet communication hole 5 ab that communicates with the remaining second refrigerant channel or channels 2 a is formed. Of the opposite ends of the main body 10 in the refrigerant flowing direction, the end provided with the first inlet communication hole 3 aa and the first inlet communication hole 3 ab is provided with the second outlet communication hole 6 aa that extends in the direction of arrangement of the second refrigerant channels 2 a. Among the second refrigerant channels 2 a, the second outlet communication hole 6 aa communicates with all of the second refrigerant channels 2 a communicating with the second inlet communication hole 5 aa and also communicates with one or more of the second refrigerant channels 2 a (corresponding to the “second second refrigerant channel group” described above) communicating with the second inlet communication hole 5 ab. Moreover, the second outlet communication hole 6 ab that communicates with the remaining second refrigerant channel or channels 2 a (corresponding to the “first first refrigerant channel group” described above) communicating with the second inlet communication hole 5 ab is formed. In this case, first ends of the second inlet communication hole 5 aa and the second outlet communication hole 6 ab are open and are connected to the second inlet connection pipe 5 and the second outlet connection pipe 6, respectively, so as to communicate with the outside. Even with the above configuration, the first refrigerant and the second refrigerant can exchange heat in a countercurrent manner, so that advantages similar to those of the heat exchanger 8 c shown in FIG. 4 can be achieved.

Furthermore, although the communication hole corresponding to the first inlet communication hole 3 a in the heat exchanger 8 according to Embodiment 1 is divided into two holes (i.e., the first inlet communication hole 3 aa and the first inlet communication hole 3 ab) in the heat exchanger 8 c according to Embodiment 4 (the same applies to the first outlet communication hole 4 aa and the first outlet communication hole 4 ab, etc.), as shown in FIG. 4, the configuration is not limited to this. Specifically, the communication hole may be divided into three or more holes so that the number of times each refrigerant is turned around is increased. In this case, depending on the divided configuration, two first outlet communication holes 4 ab would be disposed at one end of the first refrigerant channels 1 a in the direction of arrangement thereof, causing the first refrigerant to flow into or out from the holes. Accordingly, the refrigerant flow paths can be made longer while maintaining the current size of the heat exchanger, whereby the heat exchanging performance can be further enhanced.

Furthermore, the turnaround refrigerant-flow-path configuration of the heat exchanger 8 c according to Embodiment 4 is also applicable to Embodiment 2 and Embodiment 3.

Embodiment 5

A heat exchanger 8 d according to Embodiment 5 will now be described by focusing mainly on differences from the configuration and the operation of the heat exchanger 8 b according to Embodiment 3.

(Configuration of Heat Exchanger 8 d)

FIG. 5 illustrates the structure of the heat exchanger 8 d according to Embodiment 5 of the present invention. Specifically, FIG. 5( a) is a perspective view of the heat exchanger 8 d, FIG. 5( b) is a plan view as viewed in a direction indicated by an arrow A in FIG. 5( a), and FIG. 5( c) is a side view as viewed in a direction indicated by an arrow B in FIG. 5( a).

As shown in FIG. 5, a first convergence hole 31 a that communicates with the first inlet communication hole 3 a and a first convergence hole 31 b that communicates with the first inlet communication hole 3 b are formed in the direction of arrangement of the first inlet communication hole 3 a and the first inlet communication hole 3 b. Moreover, a first intermediate convergence hole 41 a that communicates with both the first outlet communication hole 4 a and the first outlet communication hole 4 b is formed in the direction of arrangement thereof.

Furthermore, a second intermediate convergence hole 51 a that communicates with both the second inlet communication hole 5 a and the second inlet communication hole 5 b is formed in the direction of arrangement thereof. Moreover, a second convergence hole 61 a that communicates with the second outlet communication hole 6 a and a second convergence hole 61 b that communicates with the second outlet communication hole 6 b are formed in the direction of arrangement of the second outlet communication hole 6 a and the second outlet communication hole 6 b.

First ends of the first convergence hole 31 a, the first convergence hole 31 b, the second convergence hole 61 a, and the second convergence hole 61 b are open and are connected to the first inlet connection pipe 3, the first outlet connection pipe 4, the second outlet connection pipe 6, and the second inlet connection pipe 5, respectively, so as to communicate with the outside. The opposite ends of the first intermediate convergence hole 41 a and the second intermediate convergence hole 51 a are closed by, for example sealing members. Therefore, the surface of the main body 10 that is opposite the surface thereof connected to the first inlet connection pipe 3 and the second outlet connection pipe 6 is connected to the first outlet connection pipe 4 and the second inlet connection pipe 5.

When viewed in the direction of the arrow A (plan view) in FIG. 5, the first convergence hole 31 a, the first convergence hole 31 b, the first intermediate convergence hole 41 a, the second intermediate convergence hole 51 a, the second convergence hole 61 a, and the second convergence hole 61 b are all formed at the same side (i.e., at the right side). However, the configuration is not limited to this. Specifically, for example, the first convergence hole 31 a may be formed at any position so long as it communicates with the first inlet communication hole 3 a and has an opening oriented toward the outside. This similarly applies to the first convergence hole 31 b, the second convergence hole 61 a, and the second convergence hole 61 b. The first intermediate convergence hole 41 a may be formed at any position so long as the position thereof is parallel to the direction of arrangement of the first outlet communication hole 4 a and the first outlet communication hole 4 b. This similarly applies to the second intermediate convergence hole 51 a.

Furthermore, as shown in FIG. 5, the extending direction of the first intermediate convergence hole 41 a does not necessarily need to be orthogonal to the extending direction of the first outlet communication hole 4 a and the first outlet communication hole 4 b. This similarly applies to the second intermediate convergence hole 51 a.

The first convergence hole 31 a corresponds to “first-convergence-hole inflow section” according to the present invention, and the first convergence hole 31 b corresponds to “first-convergence-hole outflow section” according to the present invention. The second convergence hole 61 b corresponds to “second-convergence-hole inflow section” according to the present invention, and the second convergence hole 61 a corresponds to “second-convergence-hole outflow section” according to the present invention.

(Heat Exchanging Operation of Heat Exchanger 8 d)

Next, a heat exchanging operation between the first refrigerant and the second refrigerant in the heat exchanger 8 d will be described with reference to FIG. 5.

The first refrigerant flows into the first convergence hole 31 a via the first inlet connection pipe 3 and then flows into the first inlet communication hole 3 a. The first refrigerant flowing into the first inlet communication hole 3 a flows through the first refrigerant channels 1 a and then flows out to the first outlet communication hole 4 a. The first refrigerant flowing out to the first outlet communication hole 4 a flows out to the first outlet communication hole 4 b via the first intermediate convergence hole 41 a. The first refrigerant flowing out to the first outlet communication hole 4 b flows through the first refrigerant channels 1 b and then flows out to the first inlet communication hole 3 b. The first refrigerant flowing out to the first inlet communication hole 3 b travels through the first convergence hole 31 b and flows out via the first outlet connection pipe 4.

The second refrigerant flows into the second convergence hole 61 b via the second inlet connection pipe 5 and then flows into the second outlet communication hole 6 b. The second refrigerant flowing into the second outlet communication hole 6 b flows through the second refrigerant channels 2 b and then flows out to the second inlet communication hole 5 b. The second refrigerant flowing out to the second inlet communication hole 5 b flows out to the second inlet communication hole 5 a via the second intermediate convergence hole 51 a. The second refrigerant flowing out to the second inlet communication hole 5 a flows through the second refrigerant channels 2 a and then flows out to the second outlet communication hole 6 a. The second refrigerant flowing out to the second outlet communication hole 6 a travels through the second convergence hole 61 a and flows out via the second outlet connection pipe 6.

The first refrigerant flowing through the first refrigerant channels 1 a and the second refrigerant flowing through the second refrigerant channels 2 a exchange heat in a countercurrent manner via a partition between the refrigerant channels. Furthermore, the first refrigerant flowing through the first refrigerant channels 1 b and the second refrigerant flowing through the second refrigerant channels 2 b exchange heat in a countercurrent manner via a partition between the refrigerant channels. Although the first refrigerant flowing through the first refrigerant channels 1 b and the second refrigerant flowing through the second refrigerant channels 2 a have a parallel-current relationship, it is needless to say that the two refrigerants exchange heat via a partition between the refrigerant channels.

Advantages of Embodiment 5

In the heat exchanger 8 d described above, if the sectional area of the channels is to be reduced and the refrigerant flow paths are to be extended for maximizing the heat exchanging performance in accordance with the operating conditions and the physical properties of the refrigerants, the refrigerant flow paths can be turned around inside. Therefore, in addition to the advantages of the heat exchanger 8 c according to Embodiment 3, the heat exchanging performance can be maximized while minimizing the size of the heat exchanger 8 d.

Furthermore, since the first intermediate convergence hole 41 a and the like for turning around the refrigerant flow paths are formed within the main body 10 of the heat exchanger 8 d, additional pipes do not need to be provided, whereby the heat exchanger 8 d can be made compact.

Although the first refrigerant and the second refrigerant are both made to flow by being turned around in the heat exchanger 8 d according to Embodiment 5, the configuration is not limited to this. One of the refrigerants may be made to turn around, whereas the other refrigerant may be made to flow linearly as in Embodiment 4. In this case, the refrigerant to be made to turn around may be selected in accordance with the operating conditions and the physical properties of the refrigerants in the heat exchanger so that a favorable heat exchanger with high heat transferability and low pressure loss can be obtained.

Embodiment 6

The heat exchanger according to each of Embodiment 1 to Embodiment 5 described above is installed in a refrigeration cycle apparatus, such as an air-conditioning apparatus, a hot-water storage apparatus, and a refrigerator. The refrigeration cycle apparatus according to Embodiment 6 is described as being equipped with the heat exchanger 8 according to Embodiment 1 as an example.

(Configuration of Refrigeration Cycle Apparatus 200)

FIG. 6 is a refrigerant circuit diagram illustrating an example of the refrigeration cycle apparatus according to Embodiment 6 of the present invention.

As shown in FIG. 6, a refrigeration cycle apparatus 200 includes a first refrigerant circuit formed by connecting a first compressor 230, a first radiator 231, the heat exchanger 8, a first pressure-reducing device 232, and a first cooler 233 in that order by using a refrigerant pipe. In the heat exchanger 8, the first inlet connection pipe 3 is connected to the first radiator 231 by the refrigerant pipe, and the first outlet connection pipe 4 is connected to the first pressure-reducing device 232 by the refrigerant pipe. The first refrigerant circuit operates based on a vapor-compression refrigeration cycle by causing the first refrigerant, which is a high-temperature refrigerant, to circulate therethrough.

Moreover, the refrigeration cycle apparatus 200 includes a second refrigerant circuit formed by connecting a second compressor 240, a second radiator 241, a second pressure-reducing device 242, and the heat exchanger 8 in that order by using a refrigerant pipe. In the heat exchanger 8, the second inlet connection pipe 5 is connected to the second pressure-reducing device 242 by the refrigerant pipe, and the second outlet connection pipe 6 is connected to the second compressor 240 by the refrigerant pipe. The second refrigerant circuit operates based on a vapor-compression refrigeration cycle by causing the second refrigerant, which is a low-temperature refrigerant, to circulate therethrough.

Each of the first refrigerant and the second refrigerant used is a refrigerant, such as carbon dioxide, an HFC-based refrigerant, an HC-based refrigerant, an HFO-based refrigerant, or ammonia, or a refrigerant mixture containing these refrigerants. The following description of Embodiment 6 will be directed to a case where carbon dioxide is used as the first refrigerant.

(Operation of Refrigeration Cycle Apparatus 200)

The first refrigerant in a gas state is compressed by the first compressor 230 and is discharged therefrom as a refrigerant in a high-temperature high-pressure supercritical state. The first refrigerant in the high-temperature high-pressure supercritical state flows into the first radiator 231 and exchanges heat with, for example, air so as to transfer heat thereto, thereby becoming a refrigerant in a high-pressure supercritical state. The first refrigerant in the high-pressure supercritical state flows into the heat exchanger 8 and is cooled by transferring heat to the second refrigerant flowing through the second refrigerant circuit in the heat exchanger 8, and then flows into the first pressure-reducing device 232 where the first refrigerant is reduced in pressure, thereby becoming a low-temperature low-pressure two-phase gas-liquid refrigerant. This low-temperature low-pressure two-phase gas-liquid refrigerant flows into the first cooler 233 where the refrigerant exchanges heat with, for example, air so as to evaporate, thereby becoming a refrigerant in a low-temperature low-pressure gas state. The first refrigerant in the low-temperature low-pressure gas state is suctioned into the first compressor 230 again so as to be compressed.

The second refrigerant in a gas state is compressed by the second compressor 240 and is discharged therefrom as a refrigerant in a high-temperature high-pressure gas state. The second refrigerant in the high-temperature high-pressure gas state flows into the second radiator 241 and exchanges heat with, for example, air so as to condense, thereby becoming a refrigerant in a high-pressure liquid state. The second refrigerant in the high-pressure liquid state flows into the second pressure-reducing device 242 where the second refrigerant is reduced in pressure, thereby becoming a low-temperature low-pressure two-phase gas-liquid refrigerant. This low-temperature low-pressure two-phase gas-liquid refrigerant flows into the heat exchanger 8 and evaporates by receiving heat from the first refrigerant flowing through the first refrigerant circuit in the heat exchanger 8, thereby becoming a refrigerant in a low-temperature low-pressure gas state. The second refrigerant in the low-temperature low-pressure gas state is suctioned into the second compressor 240 again so as to be compressed.

Advantages of Embodiment 6

In the refrigeration cycle apparatus 200 having the above-described configuration, a high degree of supercooling of the first refrigerant flowing out from the first radiator 231 can be ensured, so that the efficiency of the refrigeration cycle apparatus 200 can be significantly improved. In particular, because carbon dioxide is used as the first refrigerant in the above-described example, the efficiency of the refrigeration cycle apparatus 200 is particularly improved when the first refrigerant at a critical point or higher transfers heat to the second refrigerant in the heat exchanger 8.

Furthermore, the compactness of the heat exchanger 8 contributes to compactness of the entire refrigeration cycle apparatus 200.

Although carbon dioxide is used as an example of the first refrigerant flowing through the first refrigerant circuit in the above description, the first refrigerant is not limited to carbon dioxide; it is needless to say that a refrigerant, such as an HFC-based refrigerant, an HC-based refrigerant, an HFO-based refrigerant, or ammonia, or a refrigerant mixture containing these refrigerants may be used. Even in that case, a high degree of supercooling of the first refrigerant flowing out from the first radiator 231 can be ensured, so that the efficiency of the refrigeration cycle apparatus 200 can be improved.

Although the heat exchanger 8 is used as a radiator in the refrigeration cycle apparatus 200 shown in FIG. 6, the configuration is not limited to this. The heat exchanger 8 may also be used as a cooler by reversing the circulating direction of the first refrigerant by using, for example, a four-way valve.

Although the second refrigerant circuit is based on a vapor-compression refrigeration cycle in Embodiment 6, the second refrigerant may alternatively be water or brine (antifreeze), such as an ethylene glycol aqueous solution, and the second compressor 240 may be constituted of a pump.

Although the heat exchanger 8 according to Embodiment 1 is used as an example of a heat exchanger in the refrigeration cycle apparatus 200 according to Embodiment 6, as shown in FIG. 6, the heat exchanger is not limited to the above. It is needless to say that the heat exchanger used may alternatively be any of the heat exchangers 8 a to 8 d according to Embodiment 2 to Embodiment 5.

Embodiment 7

A refrigeration cycle apparatus 200 a according to Embodiment 7 will now be described by focusing mainly on differences from the configuration and the operation of the refrigeration cycle apparatus 200 according to Embodiment 6.

(Configuration of Refrigeration Cycle Apparatus 200 a)

FIG. 7 is a refrigerant circuit diagram illustrating an example of the refrigeration cycle apparatus according to Embodiment 7 of the present invention.

As shown in FIG. 7, the refrigeration cycle apparatus 200 a is obtained by removing the first radiator 231 from the configuration of the refrigeration cycle apparatus 200 according to Embodiment 6 shown in FIG. 6 and is configured to make the heat exchanger 8 cool all of the high-temperature high-pressure first refrigerant discharged from the first compressor 230. Specifically, the refrigeration cycle apparatus 200 a shown in FIG. 7 is a so-called secondary-loop refrigeration cycle apparatus. In this case, the heat exchanger 8 according to Embodiment 7 functions as both the first radiator 231 and the heat exchanger 8 in Embodiment 7.

Advantages of Embodiment 7

With the above-described configuration, the heat exchanging amount required in the heat exchanger 8 is increased, so that the percentage of the volume of the heat exchanger 8 occupying the entire refrigeration cycle apparatus 200 a is greater than that in the refrigeration cycle apparatus 200 according to Embodiment 7 equipped with the first radiator 231. In this case, the compactness of the heat exchanger 8 contributes to compactness of the entire refrigeration cycle apparatus 200 a.

Although the heat exchanger 8 is used as a radiator in the refrigeration cycle apparatus 200 a shown in FIG. 7, the configuration is not limited to this. The heat exchanger 8 may also be used as a cooler by reversing the circulating direction of the first refrigerant by using, for example, a four-way valve.

Embodiment 8

A refrigeration cycle apparatus according to Embodiment 8 is described as being equipped with the heat exchanger 8 according to Embodiment 1 as an example.

(Configuration of Refrigeration Cycle Apparatus 200 b)

FIG. 8 is a refrigerant circuit diagram illustrating an example of the refrigeration cycle apparatus according to Embodiment 8 of the present invention.

As shown in FIG. 8, a refrigeration cycle apparatus 200 b includes a refrigerant circuit formed by connecting a compressor 250, a radiator 251, the heat exchanger 8, a pressure-reducing device 252, and a cooler 253 in that order by using a refrigerant pipe. Furthermore, a bypass pipe 255 branching off from the refrigerant pipe between the heat exchanger 8 and the pressure-reducing device 252 is connected to an injection port 256 provided in a compression chamber of the compressor 250, or is connected between the compressor 250 and the cooler 253, although not shown. In the bypass pipe 255, a bypass pressure-reducing device 254 and the heat exchanger 8 are disposed in that order from a branch point of the refrigerant pipe between the heat exchanger 8 and the pressure-reducing device 252.

In the heat exchanger 8, the first inlet connection pipe 3 is connected to the radiator 251 by the refrigerant pipe, and the first outlet connection pipe 4 is connected to the pressure-reducing device 252 by the refrigerant pipe. Furthermore, in the heat exchanger 8, the second inlet connection pipe 5 is connected to the bypass pressure-reducing device 254 by the refrigerant pipe, and the second outlet connection pipe 6 is connected to the injection port 256 of the compressor 250 by the refrigerant pipe, or is connected between the compressor 250 and the cooler 253, although not shown.

(Operation of Refrigeration Cycle Apparatus 200 b)

A gas refrigerant is compressed by the compressor 250 and is discharged therefrom as a high-temperature high-pressure gas refrigerant. This high-temperature high-pressure gas refrigerant flows into the radiator 251 and exchanges heat with, for example, air so as to transfer heat thereto. Then, the high-pressure refrigerant (high-temperature refrigerant) flowing out from the radiator 251 flows into the heat exchanger 8. The high-pressure refrigerant (high-temperature refrigerant) flowing into the heat exchanger 8 is cooled by transferring heat to a low-temperature refrigerant flowing out from the bypass pressure-reducing device 254, and then flows into the pressure-reducing device 252 so as to be reduced in pressure, thereby becoming a low-temperature low-pressure two-phase gas-liquid refrigerant. This low-temperature low-pressure two-phase gas-liquid refrigerant flows into the cooler 253 and exchanges heat with, for example, air so as to evaporate, thereby becoming a low-temperature low-pressure gas refrigerant. This low-temperature low-pressure gas refrigerant is suctioned into the compressor 250 again so as to be compressed.

Before flowing into the pressure-reducing device 252, a portion of the refrigerant flowing out from the heat exchanger 8 diverges and flows into the bypass pipe 255. The refrigerant flowing into the bypass pipe 255 is reduced in pressure by the bypass pressure-reducing device 254 so as to become a low-temperature two-phase gas-liquid refrigerant (low-temperature refrigerant), which then flows into the heat exchanger 8. The low-temperature two-phase gas-liquid refrigerant (low-temperature refrigerant) flowing into the heat exchanger 8 is heated by receiving heat from the high-temperature refrigerant, and is injected into the compression chamber via the injection port 256 of the compressor 250.

The refrigerant circulating through the refrigeration cycle apparatus 200 b is a refrigerant, such as carbon dioxide, an HFC-based refrigerant, an HC-based refrigerant, an HFO-based refrigerant, or ammonia, or a refrigerant mixture containing these refrigerants.

Advantages of Embodiment 8

In the refrigeration cycle apparatus 200 b having the above-described configuration, a high degree of supercooling of the refrigerant flowing out from the radiator 251 can be ensured, so that the efficiency of the refrigeration cycle apparatus 200 b can be significantly improved.

Furthermore, in the refrigeration cycle apparatus 200 b shown in FIG. 8, the higher the saturation temperature (gas-liquid equilibrium temperature) of the low-temperature refrigerant flowing into the injection port 256 from the heat exchanger 8, the higher the efficiency of the compressor 250, whereby the required power can be reduced.

Furthermore, as shown in FIG. 8, when the high-temperature refrigerant flowing out from the radiator 251 is cooled by the heat exchanger 8, if the temperature of the high-temperature refrigerant flowing out from the radiator 251 is relatively high particularly due to a high outside air temperature, a sufficiently large temperature difference between the high-temperature refrigerant and the low-temperature refrigerant can be ensured in the heat exchanger 8. Therefore, the low-temperature refrigerant to be injected into the compression chamber of the compressor 250 via the injection port 256 can be maintained at a higher temperature, whereby high efficiency of the first compressor 230 can be ensured.

In a case where the other end of the bypass pipe 255 is connected between the compressor 250 and the cooler 253, the flow rate of the refrigerant flowing through the cooler 253 can be reduced without lowering the refrigeration effect, as compared with a case where the heat exchanger 8 is not used. In particular, when the pipe between the compressor 250 and the cooler 253 is long, performance deterioration caused by an increase in pressure loss can be suppressed.

Furthermore, the compactness of the heat exchanger 8 contributes to compactness of the entire refrigeration cycle apparatus 200 b.

REFERENCE SIGNS LIST

-   -   1 first refrigerant path 1 a, 1 b first refrigerant channel 2         second refrigerant path 2 a, 2 b second refrigerant channel 3         first inlet connection pipe 3 a, 3 aa, 3 ab, 3 b first inlet         communication hole 4 first outlet connection pipe 4 a, 4 aa, 4         ab, 4 b first outlet communication hole 5 second inlet         connection pipe 5 a, 5 aa, 5 ab, 5 b second inlet communication         hole 6 second outlet connection pipe 6 a, 6 aa, 6 ab, 6 b second         outlet communication hole 8, 8 a to 8 d heat exchanger 10 main         body 31 first inlet convergence hole 31 a, 31 b first         convergence hole 41 first outlet convergence hole 41 a first         intermediate convergence hole 51 second inlet convergence hole         51 a second intermediate convergence hole 61 second outlet         convergence hole 61 a, 61 b second convergence hole 200, 200 a,         200 b refrigeration cycle apparatus 230 first compressor 231         first radiator 232 first pressure-reducing device 233 first         cooler 240 second compressor 241 second radiator 242 second         pressure-reducing device 250 compressor 251 radiator 252         pressure-reducing device 253 cooler 254 bypass pressure-reducing         device 255 bypass pipe 256 injection port 

1-14. (canceled)
 15. A heat exchanger, comprising: a main body including a first refrigerant path in which a plurality of first refrigerant channels through which a first refrigerant flows are arranged in a single row; a second refrigerant path in which a plurality of second refrigerant channels through which a second refrigerant flows are arranged in a single row, the first refrigerant path and the second refrigerant path being formed integrally to one another, the main body comprising; first communication holes that are formed at opposite ends of the first refrigerant path, as holes extending through the main body in a direction of arrangement of the plurality of first refrigerant channels, and communicate with the plurality of first refrigerant channels; and second communication holes that are formed at opposite ends of the second refrigerant path, as holes extending through the main body in a direction of arrangement of the plurality of second refrigerant channels, and communicate with the plurality of second refrigerant channels, wherein the first refrigerant flows into one of the first communication holes formed at the opposite ends of the first refrigerant path, flows through the first refrigerant channels, and flows outside via the other first communication hole, wherein the second refrigerant flows into one of the second communication holes formed at the opposite ends of the second refrigerant path, flows through the second refrigerant channels, and flows outside via the other second communication hole, and wherein the first refrigerant channels and the second refrigerant channels extend in parallel to each other and are disposed adjacent to each other, and the first refrigerant and the second refrigerant exchange heat via a partition at adjacent surfaces of the first refrigerant channels and the second refrigerant channels.
 16. The heat exchanger of claim 15, wherein, of the first communication holes formed at the opposite ends of the first refrigerant path and the second communication holes formed at the opposite ends of the second refrigerant path, the first communication hole and the second communication hole located at a same side are displaced from each other by a predetermined amount in a channel-extending direction of the first refrigerant path or the second refrigerant path.
 17. The heat exchanger of claim 15, wherein, in an extending direction of each first communication hole, the first communication hole has one end that is closed and another end that is open such that the first refrigerant flows into and out from the open end thereof, and wherein, in an extending direction of each second communication hole, the second communication hole has one end that is open and another end that is closed such that the second refrigerant flows into and out from the open end thereof.
 18. The heat exchanger of claim 15, wherein at least one of the first communication holes formed at the opposite ends of the first refrigerant path is divided into multiple sections, and wherein the multiple sections include one first divided-communication-hole inflow section into which the first refrigerant flows from outside and that makes the first refrigerant flow to one or more of the plurality of first refrigerant channels, at least one first divided-communication-hole turnaround section that causes the first refrigerant flowing from the one or more of the first refrigerant channels to turn around and flow to a different one or more of the first refrigerant channels other than the one or more of the first refrigerant channels, and one first divided-communication-hole outflow section that causes the first refrigerant flowing from the first divided-communication-hole turnaround section through the different one or more of the first refrigerant channels to flow outside, so that the first refrigerant flows through the first refrigerant path by being turned around therein.
 19. The heat exchanger of claim 18, wherein at least one of the second communication holes formed at the opposite ends of the second refrigerant path is divided into multiple sections, and wherein the multiple sections include one second divided-communication-hole inflow section into which the second refrigerant flows from outside and that makes the second refrigerant flow to one or more of the plurality of second refrigerant channels, at least one second divided-communication-hole turnaround section that causes the second refrigerant flowing from the one or more of the second refrigerant channels to turn around and flow to a different one or more of the second refrigerant channels other than the one or more of the second refrigerant channels, and one second divided-communication-hole outflow section that causes the second refrigerant flowing from the second divided-communication-hole turnaround section through the different one or more of the second refrigerant channels to flow outside, so that the second refrigerant flows through the second refrigerant path by being turned around therein.
 20. The heat exchanger of claim 15, wherein the first refrigerant path has a plurality of first refrigerant channel groups, each of which is a set of plurality of the first refrigerant channels, and wherein the second refrigerant path has a plurality of second refrigerant channel groups, each of which is a set of plurality of the second refrigerant channels.
 21. The heat exchanger of claim 20, wherein the plurality of first refrigerant channel groups in the first refrigerant path are disposed adjacent to each other and are arranged such that directions of arrangement of the first refrigerant channels are parallel to one another, and wherein the plurality of second refrigerant channel groups in the second refrigerant path are disposed adjacent to each other and are arranged such that directions of arrangement of the second refrigerant channels are parallel to one another, wherein a first refrigerant channel group located at one end of the plurality of first refrigerant channel groups disposed adjacent to each other is disposed adjacent to a second refrigerant channel group located at one end of the plurality of second refrigerant channel groups disposed adjacent to each other, and the direction of arrangement of the first refrigerant channels in the first refrigerant channel group is parallel to the direction of arrangement of the second refrigerant channels in the second refrigerant channel group, wherein the first communication holes communicate with all of the first refrigerant channels constituting the plurality of first refrigerant channel groups, and wherein the second communication holes communicate with all of the second refrigerant channels constituting the plurality of second refrigerant channel groups.
 22. The heat exchanger of claim 20, wherein the first refrigerant channel groups in the first refrigerant path and the second refrigerant channel groups in the second refrigerant path are alternately arranged adjacent to each other, and the directions of arrangement in all of the groups of refrigerant channels are parallel to one another, wherein the first communication holes are formed at opposite ends of each first refrigerant channel group, and opposite ends of each first communication hole in an extending direction thereof are closed, and wherein the second communication holes are formed at opposite ends of each second refrigerant channel group, and opposite ends of each second communication hole in an extending direction thereof are closed.
 23. The heat exchanger of claim 22, wherein the heat exchanger further comprises first convergence holes extending through the heat exchanger in a direction of arrangement of the plurality of first communication holes and communicating with the plurality of first communication holes; and second convergence holes extending through the main body in a direction of arrangement of the plurality of second communication holes and communicating with the plurality of second communication holes, wherein the first refrigerant flows into one of the first convergence holes formed at the opposite ends of the first refrigerant path, flows through the first refrigerant channels, and flows outside via the other first convergence hole, and wherein the second refrigerant flows into one of the second convergence holes formed at the opposite ends of the second refrigerant path, flows through the second refrigerant channels, and flows outside via the other second convergence hole.
 24. The heat exchanger of claim 23, wherein, in an extending direction of each first convergence hole of the plurality of first convergence holes, the first convergence hole has one end that is closed and another end that is open such that the first refrigerant flows into and out from the open ends thereof, and wherein, in an extending direction of each second convergence hole, the second convergence hole has one end that is closed and another end that is open such that the second refrigerant flows into and out from the open ends thereof.
 25. The heat exchanger of claim 20, wherein the main body further comprises first convergence holes each constituted of a first-convergence-hole inflow section extending through the main body and communicating with one or more of a plurality of the first communication holes located at one end of the opposite ends of the first refrigerant path and a first-convergence-hole outflow section extending through the main body and communicating with remainder of the first communication holes located at the one end; a first intermediate convergence hole extending through the main body in a direction of arrangement of a plurality of the first communication holes located at an end, which is opposite from an end provided with the first convergence hole, of the opposite ends of the first refrigerant path and communicating with the plurality of first communication holes; and second convergence holes extending through the main body in a direction of arrangement of the plurality of second communication holes and communicating with the plurality of second communication holes, wherein the first refrigerant flows into the first-convergence-hole inflow section formed at one end of the first refrigerant path, flows through one or more of the first refrigerant channel groups, travels through the first intermediate convergence hole, flows through a different one or more of the first refrigerant channel groups by being turned around therein, and flows outside via the first-convergence-hole outflow section, and wherein the second refrigerant flows into one of the second convergence holes formed at the opposite ends of the second refrigerant path, flows through the second refrigerant channels, and flows outside via the other second convergence hole.
 26. The heat exchanger of claim 20, wherein the main body further comprises first convergence holes each constituted of a first-convergence-hole inflow section extending through the main body and communicating with one or more of a plurality of the first communication holes located at one end of the opposite ends of the first refrigerant path and a first-convergence-hole outflow section extending through the main body and communicating with remainder of the first communication holes located at the one end; a first intermediate convergence hole extending through the main body in a direction of arrangement of a plurality of the first communication holes located at an end, which is opposite from an end provided with the first convergence hole, of the opposite ends of the first refrigerant path and communicating with the plurality of first communication holes; second convergence holes constituted of a second-convergence-hole inflow section extending through the main body and communicating with one or more of a plurality of the second communication holes located at one end of the opposite ends of the second refrigerant path and a second-convergence-hole outflow section extending through the main body and communicating with remainder of the second communication holes located at the one end; and a second intermediate convergence hole extending through the main body in a direction of arrangement of a plurality of the second communication holes located at an end, which is opposite from an end provided with the second convergence hole, of the opposite ends of the second refrigerant path and communicating with the plurality of second communication holes, wherein the first refrigerant flows into the first-convergence-hole inflow section formed at one end of the first refrigerant path, flows through one or more of the first refrigerant channel groups, travels through the first intermediate convergence hole, flows through a different one or more of the first refrigerant channel groups by being turned around therein, and flows outside via the first-convergence-hole outflow section, and wherein the second refrigerant flows into the second-convergence-hole inflow section formed at one end of the second refrigerant path, flows through one or more of the second refrigerant channel groups, travels through the second intermediate convergence hole, flows through a different one or more of the second refrigerant channel groups by being turned around therein, and flows outside via the second-convergence-hole outflow section.
 27. The heat exchanger of claim 15, wherein the first refrigerant and the second refrigerant flow in directions for forming a countercurrent in at least one or more of the refrigerant channels.
 28. A refrigeration cycle apparatus, comprising: the heat exchanger of claim
 15. 